Ext.onReady(function(){
    var tabs = new Ext.TabPanel({
        renderTo: 'MainTabContainer',
        activeTab: 0,
        frame:true,
        defaults:{autoHeight: true, autoWidth: true},
        items:[
            {contentEl:'extFormComponents', title: 'Form Components'},
            {contentEl:'extComplex', title: 'Complex Widgets'},
            {contentEl:'extFancy', title: 'The Oomph!'}
        ]
    });
});